A STUDY ON DYNAMIC CHARACTERISTICS OF TRADITIONAL WOODEN BUILDING BY MICRO TREMOR MEASUREMENT

为了了解传统木结构建筑的动力特性，对黑州宫殿遗址和和鱼寺建筑的重建建筑进行了微震测量。通过FFT分析，我们得到了如下认识。重建建筑物：4~10 Hz四个谱峰，三种振型，从低到低依次为：脊向平行模、梁向平行模和扭转振型。分析得到的固有频率和振型与低频下的测量结果吻合较好。和乐裕基塔：10赫兹以下的三个固有频率，分别为0.9赫兹、2.5赫兹和4.2赫兹。0.9赫兹振型为斜向平行振型，2.5赫兹振型为垂直第二振型，在5层楼高处为倒相振型。5层的轨迹有时表现为平行振动，有时表现为圆周振动。刚度值随着楼层数的增加而减小。近藤和…More Chumon：每栋建筑在10赫兹以下有两个固有频率，近藤为1.80赫兹和2.07赫兹，楚蒙为1.56赫兹和1.80赫兹。两栋建筑的主振型在梁方向上为平行振型，第二振型在屋脊方向上为平行振型。阻尼系数为1.7-4.4%。根据自振频率计算的近藤第一层的刚度为2.79-3.69×10^4 kg/cm，柱子抗摇摆引起的刚度百分比为75-81%。Dai-Kodo：10赫兹以下的4个固有频率，分别为1.7赫兹、2.1赫兹、2.5赫兹和4.1赫兹。主振型在梁方向上为平行振型，第二振型在脊线方向上为平行振型。第三个模式是光束方向的扭转模式。减振因子为1.9-2.5%。根据固有频率计算得到的Dai-Kodo刚度值为1.9-2.5%。由固有频率计算得到的大理石刚度值为1.62×10~(-4)~2.50×10~(-4)kg/cm，抗摆柱刚度的百分比为88~95%。较少

To understand dynamic characteristics of traditional wooden buildings, micro tremor measurements were performed on rebuilt buildings of Heijo palace site and Horyuji buildings. By the FFT analysis we obtained the knowledges as the following.1. Rebuilt buildings : Four spectrum peaks from 4Hz to 10Hz, and three vibration modes which were parallel mode in the ridge direction, parallel mode in the beam direction and torsional mode in order from lower frequency. Analytic natural frequencies and vibration modes agreed well with those of measurement in lower frequencies.2. Horyuji pagoda : Three natural frequencies under 10Hz, which were 0.9Hz, 2.5Hz, and 4.2Hz. Vibration mode at 0.9Hz was parallel mode in the diagonal direction and at 2.5Hz it was virtical second mode with phases reversed at the height of 5th story culumn botom. Locus of 5th story shows sometimes parallel vibration and sometimes circular vibration. Values of stiffness which decrease as the story number increase.3. Kondo and … More Chumon : Two natural frequencies for each building under 10Hz, which were 1.80Hz and 2.07Hz for kondo and 1.56Hz and 1.80Hz for Chumon. For both buildings, primary vibration mode was parallel mode in the beam direction and second mode was parallel mode in the ridge direction. Damping factors were 1.7-4.4%. Values of stiffness of Kondo first story calculated from natural frequencies were 2.79-3.69*10^4kg/cm and the percentage of stiffness due to column rocking resistance is considered to be 75-81%.4. Dai-kodo : Four natural frequencies under 10Hz, which were 1.7Hz, 2.1Hz, 2.5Hz and 4.1Hz. Primary vibration mode was parallel mode in the beam direction and second mode was parallel mode in the ridge direction. The Third mode was twist mode in the beam direction. Damping factors were 1.9-2.5%. Values of stiffness of Dai-kodo calculated from natural frequencies were 1.9-2.5%. Values of stiffness of Dai-kodo calculated from natural frequencies were 1.62*10^4 -2.50*10^4 kg/cm and the percentage of stiffness due to column rocking resistance is considered to be 88-95%. Less